General Description

The purpose of this install is to enable use of a RAID Set created by the onboard BIOS RAID controller and thereby opening up the possibility to dualboot Windows from a partition on the RAID Set.

History

In linux 2.4 the ATARAID kernel framework provided support for Fake Raid (software RAID assisted by the BIOS). For linux 2.6 the device-mapper framework can do, among other nice things like LVM and EVMS, the same kind of work as ATARAID in 2.4. While the new code handling the RAID's I/O still runs in the kernel, device-mapper stuff is generally configured by a userspace application. It was clear that when using the device-mapper for RAID, detection would go to userspace.

Heinz Maulshagen created the dmraid tool to detect RAID sets and create mappings for them. The controllers supported are (mostly cheap) Fake-RAID IDE / SATA controllers which have BIOS functions on it. Most common ones are: Promise Fasttrack controllers as well as HPT 37x, Intel, VIA and LSI. Also serial ata RAID controllers like Silicon Image Medley and Nvidia Nforce are supported by the program.

Tested with nforce4-chipset on Core Dump i686 and x86_64. Works with dualbooted Windows XP.

Tested with sil3512-chipset on Overlord x86_64.

For more info on supported hardware check gentoo-guide down low.

Backup

Backup all data before playing with RAID, what you do with your hardware is only your own fault. Data on RAID Stripes are highly vulnerable to disk failures, create regular backups.

Install dmraid

/dev/mapper/control <-- Created by device-mapper
/dev/mapper/sil_aiageicechah <-- A RAID set on a Silicon Image chipset
/dev/mapper/sil_aiageicechah1 <-- First partition on this RAID set

If there is only one file: control in /dev/mapper/ check if your chipset module was loaded with lsmod if it is then dmraid does not support this controller or there are no RAID Sets on the system (check RAID BIOS Setup again). If you did everything correct then your current options are to use Software RAID, this means no dualbooted RAID system, or to get a supported controller.

Also if you only have one set per chipset you could enter: /dev/mapper/sil*

Partition the RAID Set

Create the proper partitions

Note: Now would be a good time to install the other OS since this most likely is the plan. If installing Windows XP to C: then the boot partition should be changed to type: hidden fat32 [1B] to hide it during the Windows installation and then changed back to type: linux [83] for GRUB.

Of course a reboot unfortunately requires some of the above steps to be repeated.

If you do not find your newly created partitions under Set Filesystem Mountpoints you want to do the following:

/dev/mapper/control <-- Created by device-mapper
/dev/mapper/nvidia_geceiece <-- The whole RAID set.
/dev/mapper/nvidia_geceiece1 <-- First partition on this RAID set

If there is no /dev/mapper/ directory you will have to load the required modules before running "dmraid -ay".

If there is only one file control in /dev/mapper/ then dmraid does not support this controller or there are no RAID Sets on the system. Current options are to use Software RAID, this means no dualbooted RAID system, or to get a supported controller.

Partition the RAID Set

Create the proper partitions

Deactivate all RAID devices

Reactivate the newly created RAID devices

Note: Now would be a good time to install the other OS since this most likely is the plan. If installing Windows XP to c: then the boot partition should be changed to type: hidden fat32 [1B] during the Windows installation and then changed back to type: linux [83] for GRUB.

Of course a reboot unfortunately requires some of the above steps to be repeated.

Install and Configure Arch

For instance use three consoles; the quickinstall script to get all files on the system, the setup gui to configure the system and chroot to install grub and finally a cfdisk reference since RAID sets have weird names.

tty1: /arch/quickinstall, chroot and grubtty2: /arch/setuptty3: cfdisk for a reference in spelling, partition table and geometry of the RAID Set. Leave it running and switch to when needed.